Capacitive-coupling control system



' Feb. 14, 1928.

1,658,804 L. L. JONES CAPACITIVE COUPLING CONTROL SYSTEM Original Filed Dec. 15, 1922 INVENTOR .ZESTERL. o/vas Patented F eb. 14, 1928.

UNITED s'ra'rss l,65&,804

PATENT OFFECE,

LESTER L. JONES, E ORADELL, NEW JERSEY.

GAPACIT-IVE-COUPLING CONTROL SYSTEM.

Original application filed December 15, 1922, Serial No. 607,046. Divided and this application filed September 21, 1926.

This invention relates to a thermionic tube circuit system, and more particularly to a tube circuit system wherein the thermionic tube functions as a relay or amplifier of energy transmitted from the input or grid circuit to the output or plate circuit; and has special reference to the provision of a tube circuit system in which the re-transler or teed-back of energy from the plate to the in grid circuit due to the capacitive coupling between the plate andgrid is made controllable and may be eiiectively minimized or eliminated.

This application is a division of my cois pending application Serial #607,046 filed Doc. 15, 1922.

In the use and operation of thermionic tubes as employed for example in the transmission and reception of audio and radiant an energy, it is well known that due to the unshieldable capacity between the plate and grid of the tube, a re-transterror teed-back of energy from the tube to the input circuit takes place. This energy or power feedis back is highly objectionable, especially in relay, amplifying or modulating circuits, because itgives rise to distortionof the input voltage power wave form and to incipient or sustained oscillations in the grid circuit. To reduce the feed-back or re-transferrence of energy to avoid these defects, it has been common engineering design to construct the tube with a minimum of capacity between the grid and plate. This reduction in the capacity between the plate and the grid,

however, merely redluces but does not eliminate the re-transferrence of energy, the reduction of the capacity being in itself disadvantageous, since it reduces the efiiciency of the tube system.

When the tube is employed as an audio frequency amplifier, it is found that when the amplifier is made efiicient, that is, to amplify 20 or more times audibility per stage, the tone quality is defective because an abrupt strong current pulse will'set the amplifier system into an oscillation which is unduly prolonged by the re-transfer of energy from the plate circuit to the grid circuit through the gridi-plate tube capaclty. If the amplifier is made very efiicient, this re-transfer of energy will be enough to sustain the oscillation and there will result a prolonged whistle. An expedient for minimizing this Serial No. 136,864.

effect has been to shunt the output impedance of theoutput circuit by a large condenser, but this expedient has the disadvantage of suppressing the higher tone tre- 'quencies. In order to obviate this objection, it has been also attempted to shunt a high resistance around the input circuit from. the grid to the filament, this being objectionable,- however, in that the etliciency of the system is materially reduced.

Then the thermionic tube is utilized in the transmission or broadcastingwot radiantenergy, the energy or power feedback due to the capacitive coupling between the plate and grid'circuits is also found to be decidedly deleterious in its effects. The theoretically best type of tube transmitter from the operating viewpoint is the master oscillator or separately excited grid system. This system has not worked out practically in the past, mainly because of the energy transfer back to the inaster oscillator through the tube capacity coupling which in the case of transmitting tubes is very large. This oscillating energy feed-back causes distortion of the master oscillation or sustains it to the point Where no minimum appears. To avoid this, it has been necessary to so. damp the master oscillator or the exciting grid circuit that very little amplification is obtained. This necessitates the use of master oscillation circuits of the approximate power of the antenna circuit, or many stages of amplification, the use of either resulting in such low over-all efiiciency that the system is impractical for all except very low power transmitters where the power cost is not an economic factor.

A prime desideratumof my present invention comprehends the provisionof a tube circuit system in which the feed-back or retransferrence of energy or power from the plate to the grid circuit resulting from the capacitive coupling between the circuits due to the grid-plate capacity is efi'ectively controlled so that the same may be reduced to a value below that resulting from the grid-plate capacity of the tube and which may be reducedto aminimum or entirely eliminated. By the elimination of this energy feed-back the tubes need not be designed with a minimum of capacity as is the case in the present practice, and the tubes may be designed to produce a maximum ef-- I grid-plate capacity;

a prov sion of a tube systeinof this nature in ficiency in the use and operation thereof. When employed as an audio frequency amplifier, the above-mentioned expedients need not be resorted to, and the amplifying system may be made to have the highest etficiency without that howling or distortion which results from the energy transfer back to the input circuit. Vhen employed in transmitting systems, the tube circuit system of my invention may be used to produce perfect reproduction of the modulated oscillation in power tube amplifiers stepping up over times in power per stage. Moreover, by substantially or completely eliminating the energy re-transfer due to the capacitive coupling between the circuits, I ani enabled to produce a system which gives an absolutely one-way energy transfer device with all its consequent advantages when employed in audio and radio transmitting and receiving systems.

Looked at from a broader aspect, my presentinvention contemplates the provision of means for adjusting the capacitive coupling between the grid and plate of the tube to points below the natural or gridplate capacity of the tube down to a minimum so that the energy feed-back may be reduced to magnitudes or values below that resulting from the grid-plate tube capacity. This latter control is' found desirable in a number of circuits, as for example in capacitive coupling re-generative circuits such as the Armstrong tuned wing and grid circuit, this control permitting regeneration at avalue below the natural tube capacity.

By means of the capacitive coupling con trol of my invention, moreover, the effect of the natural tube capacity may be not only reduced or eliminated, but may be re versed so as to permit tie-generative effects.

The principal objects of my present invention may be said to include. besides the provision of a capacitive feed-back control and eliminator for thermionic tubes as above referred to; the more specific provision of a tube circuit system in which the charge carried to the grid from the plate through the capacity therebetween may be neutralized in whole or in .part, thus reducing to any desired degree or completely eliminating the re-transfer of potential and the retransfer or feed-back of energy; the further provision of a tube circuit system in which a charge is impressed on the grid which may be less than, equahto or greater than in magnitude but opposite in sign to the charge impressed thereon or carried thereto from the plate circuit; the further provision of a tube circuit system in which a charge is impressed on the grid which is equal in phase and opposite in sign to the charge carried thereto from the output circuit through the and the still further which the neutralizing charge impressed on the grid is caused to vary in correspondence to 'the variations of the charge carried to the grid from the plate in the normal use and operation of the tube.

To the accomplishment of the foregoing and such other objects as may hereinafter appear, my invention consists in the elements and their relation one to the other, as hereinafter particularly described and sought to be defined in the claims, reference being had to the accompanying drawings which show a preferred embodiment of my invention, and in which:

Fig. 1 is a wiring diagrammatic view of the thermionic tube circuit system provided with an inductively coupled transformer in the plate circuit and showing my invention applied thereto,

Fig. 2 is a wiring diagrammatic view off a thermionic tube circuit system provided with a choke coil in the plate circuit and showing a modification of my invention applied thereto,

Fig. 3 is a re-arrangemcnt of the circuit system of Fig. 1 exemplifying the effect of the same as simulating'a balanced bridge.

Fig. 4 is a wiring diagrammatic view of another type of circuit showing my invention applied thereto,

Fig. 5 is a wiring diagrammatic view showing a modification of my invention applieddto a circuit of the type shown in Fig.

Fig. 6 is a cross-sectional view of a control means which may be employed as part of my invention.

Referring now more in detail to the drawings, and more particularly to Fig. 1 thereof, the thermionic tube system comprises the filament 10 which is heated to incandescencc by means of the battery 11 connected thereto for producing the electron stream, a grid 12 and a plate 13. The said grid 12 is included in a grid or energy input circuit having inductance and capacity, and which may comprise the inductance coil or inductor 14 which may be coupled for energy reception to an induction coil of an antenna circuit and a condenser 15 which may be connected in parallel withthe inductor 14, the inductor and condenser being connected to the grid and the filament by and 17 respectively. The plate 13 is included in a plate or output circuit rovided with an external or output impe anc'e 18 connected at one end by means of the conductor 19 to the plate 13 and connected at the other end by means of the conductor 20 to the positive terminal of the battery 21, the negative terminal of which is connected to the filament 10 "as clearly shown in the drawings. The output impedance 18 may, as shown, comprise the primary of an air core transformer, and is coupled to the secmeans of conductors 16V loo til

lit)

ondary 22 of the said transformer, the said secondary receiving at resonance the amphtied energy for further amplification if desired, resonance being obtained by the condenser 'As heretofore mentioned, due to the normally unshieldable capacity between the plate 13 and the grid 12 of the tube, some of the energy in the output circuit is objectionably re-transferred' or fed back to the input circuit, the grid 12 being charged by the plate 13 through the capacity therebetween. My present invention contemplates broadly the provision of means for controllably. reducing or entirely eliminating the eliect of the charge carried from the plate to the grid, the power re-transferrence being, more specifically, controllably reduced or eliminated by neutralizing the feed-back or potential or neutralizing in part or whole, the charge carried from the plate to the grid. This result 1 preferably accomplish by providing means for impressing on the grid 12 a charge which may be less than, equal to or greater than in magnitude but opposite in sign to the charge carried there to from the plate, and to this end there is provided means for creating a potential opposite to the potential on the plate and impressing the said potential on a capacity means connected to the grid. 12. -Where teed-back is desired to be entirely eliminated, the product of the said potential and the capacity is made equal to the charge transferred to the grid from the output circut. One manner of accomplishing this is exemplified in Fig. 1 of the drawings,- which shows my invention applied to an amplifying circuit and in which the potential created is made equal in phase and amplitude and opposite in sign to the potential on the plate, and the, capacity connected to the grid is preferably made equal to the measured capacity between the plate and the grid. To these ends, I provide, as shown in Fig. 1 of the drawings, an additional impedance 23 comprising a coil wound in the same direction as the output impedance coil 18 and having a number of turns equal to the num ber of turns in the winding 18, the said additional impedance being connected at one end to the conductor 20 and being connected at its other end by means of a conductor 24 to a condenser 25 which is connectedas shown to the high potential side of the input circuit, the said condenser 25 being made equal to the measured capacity between the grid 12 and the plate 13 and the capacity between the conductors or leads connected thereto (of the order of 6 mmttfis for pres ent-day receiving tubes). The additional impedance. 23 is preferably closely coupled to the output impedance 18, and this imped ance serves to produce the potential equal phase and amplitude and opposite in sign to the potential on the plate 13, these potentials being taken with reference to the filament potential. By impressing this potential on the condenser 25, it will be apparent that the grid 12 is supplied with an electric charge which is equal and opposite to the charge produced thereon as the result of the capacitive coupling between the input and output circuits neutralizing the said latter charge, and it will be further noted that by virtue of the balancing or equalizing impedance and capacity 23 and 25 respectively, the neutralizing charge varies in correspondence with the varying charge on the plate in the operation of the circuits, so that. the energy feed-back is eliminated for all variations of the grid and plate circuits, and that when once adjusted, the equalizing circuit will eliminate teed-back at all frequencies.

The effect of the charge neutralizing cir: coil: of my invention may be seen from a consideration of Fig. 3 of the drawings, which comprises a rearrangement. of the circuit system shown in Fig. 1 and an arrangement of the same in a simulated balanced lori@e formation. The condenser 25 in one arm of the bridge is made equal to the natural tube capacity '26 between the grid and plate in the corresponding arm of the bridge, and the additional impedance 23 is made equal to the output impedance 18. To minimize in a practical way any unbalance that results from the plate component of voltage in the plate circuit, the output impedance and the added impedance are closely coupled with a coupling, however, substantially less than unity. By a coupling substantially lessthan unity, I desire it to be understood that I mean that range of conplings that can be obtained withair cored transformers; and as shown in the drawings, the output impedance 18 and the added in1- pedance 23 are air core coupled. In most practical cases where the output impedance forms the primary of a transformer for the further transfer of energy, as shown in Figs. 1 and '3 of the drawings, itis sutlicient if the output impedance and the added impedance are separately and closely coupled to the secondary of the transformer.

Thus the output impedance 18 and the added impedance 23, as shown in both Figs. 1 and 3 of the drawings are separately and closely coupled to the secondary 22 ofthe transformer; and as will be seen by reference to these Figs. 1 and 3, the output and added impedances 18 and 23 are; each couplied similarly or equally to the secondary coil 22 of the coupling transformer.

Referring now to Fig. 2 of the drawings, I

show a modification of my system employed with tube circuits provided with a choke coil in the late circuit, and wherein like parts of the tu e system are designated by primed reference characters. In this system the output circuit is provided with the choke coil 18 to which maybe connected a condenser 27 leading to a second thermionic tube gen:

erally designated as 28,.and connected and coupled to the choke coil impedance 18 I provide the additional impedance 29 for creating a potential opposite in direction to the potential on the tube plate 13. The additional impedance 29 may differ in size from the output impedance l8, and as shown may be made smaller than the output impedance. The reversepotential creating impedance 29 is connected by means of the conductor 30 to a condenser 31 which in turn is connected to the high potential side 16 of the grid circuit; and the said condenser 31 may also differ in magnitude from the capacity between grid 12 and plate 13,-the capacity of this condenser 31 and the impedance of coil 29 being, however, so designed that the product of the capacity and the potential created by the impedance is substantially equal and opposite to the transferred chargeon the grid 12. This system shown in Fig.2 is not as eflicient as the balanced system shown in Figs. 1 and 3 of the drawings, but may be employed for obtaining substantial elimination of theenergy feed-back wherever a full elimination thereof is desired.

. As heretofore mentioned, my invention may be applied to tube circuits where it is found desirable to adjust the grid-plate eapacitive coupling to a point between the natural capacity of the tube and a zero value, and if desired to adjust the same in the reverse direction. In Fig. 4 of the drawings, this application of my invention is exemplified as applied to the Armstrong tuned wing and grid circuit; and referring to Fig. 4, I show the said wing and grid circuit generally designated as 34, which circuit is modified by removing the conductor 33 (shown in dotted lines) which connects the wing circuit 34 to the telephone receiver 35, and by tapping the midpoint of the inductance 36 of the wing circuit and connecting-the same by means of the conductor 37 to the telephone receivers 35, the wing circuit being further connected to the high potential side 38 of the grid circuit by means of the conductor 39, condenser 40 and conductor 41, said condenser 40 being made variable as hereinafter to be described in detail so as to vary the charge impressed upon. the high potential side of the grid circuit. In the unmodified Armstrongtuned wing and grid circuit, no advantage has been found in the use of good or high power amplifying tubes. This is due to the fact that when the wing circuit is tuned to the incoming wave, the energy feedback through the grid-plate capacity is so strong as to set the grid circuit into oscillation. When such a tube is used, it is there fore necessaryeither to detune the plate 011- cuit considerably, thus losing a large part of the selectivity of this system, or to reduce the filament or plate voltage so as to reduce the tube amplification. This latter method reduces the signal intensity although it retains the selectivity of the system. By the use of my invention and by adding my charge neutralizing circuit as described, I am enabled to operate the tuned wing and grid circuit with tubes of the highest power or amplification by reducing the back coupling to the point where the grid circuit is just about to oscillate even though the plate circuit is held in exact resonance with the incoming signal.

As heretofore mentioned, for the purpose of changing or adjusting the charge impressed on the high potential side of the grid circuit by means of the equalizing circuit of my invention, the condenser connected to the high potential side of the grid circuit may be made variable. For the purpose of preventing the variation of capacity of this condenser from varying the tuning characteristics of the grid or input circuit. I have found it desirable to provide means for varying the capacity of the input circuit simultaneously and in correspondence with the varying of the capacity in the equalizing circuit, the construction provided to this end being shown in Fig. 5 of the drawings. Referring to this figure which depicts the tube circuit shown in Fig. 1 of the drawings, like parts of which are indicated by primed reference characters, connecting the equalizing impedance 23 of the equalizing circuit to the high potential side of the grid circuit I provide a variable condenser generally designated as 25 which in the preferred construction includes three spaced plates at. b, c, the plate 0 being connected by the conductor 24 to the equalizing impedance 23, the plate a being connected to the grid by means of the lllll conductor 42, and the plate Z) being connected a is moved to the right, the capacity between the plates at and b is increased and the capacity between the plates at and c is correspondingly decreased, and as the plate a is moved to the left the capacity between the plates a and c is increased and the capacity between the plates at and 7) is correspondingly decreased in inverse ratio. In view of the negligible impedance of the coil 23 as compared with the impedance of the grid coil 14, the change in capacity between the plates (1 and b is normally effective for modifying the capacity of the grid circuit. and by the construction provided the grid circuit capacity may be maintained constant during adjustment of the plate a and during the vaessee-i riation of the charge impressed upon the grid 12'.

The three-plate condenser of my invention may constructionally take the form shown in Fig. 6 of the drawings, in which the three plates comprise cylinders or tubes a, b and c, the tubes 6' and being fixed or stationary and the tube a being telescopically movable in opposite directions within the tubes b and c. The tube 6' may be fixedly carried by a collar 44 and secured thereto by the screw 45, the said collar being threadedly received by a threaded bushing idwhich is stationarily mounted on a panel board 4'2, the panel board being secured between the shoulder l8 of the bushing 46 and the collar 44. Fitting within the tube '1 provide a tube of insulating material 49 such as hard rubber on which the tube 0 is fixed by means of the screw 50 and within which the tube a slides.

For telescopically or slidably moving the plate-tube a and indicating its position there is provided a spindle 51 which carries the tube a at one end and which is threaded the greater part of the length at the other end as shown at 52 for threaded engagement with a tapped member 53 attached to an insulating dial member fi l which carries a pointer 55. The spindle 51 is longitudinally recessed as at 56 for receiving a pin 57 fitted into the bushing 46, this to the end of constraining the spindle to move axially only upon rotation of the dial 545. With this construction, it will be apparent that upon rotation or the dial 54: in opposite directions, the spindle 51 and the condenser tubes plate a will be moved in o posits directwns for varying the capacity oetween plates at and o in inverse relation to that between the plates (2' and c. lt will be further seen that when plate I) is connected to round while plates a and 0 are connecte respectively to the grid and plate coil, the plate 72 provides a ground shield forthe small unit condenser a'c, preventing that interference presented by the hand or body of the operator.

The use and operation of my capacitive teed-back control or eliminator and the control condenser therefor will in the main be fully apparent from the above detailed description taken in connection with the many possible applications thereof. It will be seen that with my invention it am enabled to control the efiect of grid-plate capacitive coupling and vary the same to points below the natural capacity of the tube, the capacitive teed-back efiect being controllable so as to permit reduction to produce desired regeneration, to permit of complete elimination to produce an absolutely one-way energy transfor device, and so as to permit reversal where degeneration is desired to be efiiected. It will also be seen that in my capacitive coupling control the grid-plate capacitive coupling may be varied Without altering the period of the input circuit.

While I have shown my device in the preferred forms, it will be obvious that many changes and modifications maybe made in the structure disclosed without departing from the spirit of the invention, defined in the following claims.

I claim:

1. In combination, an electron discharge tube with its grid and plate electrodes, a grid or input circuit, a plate or output circuit, a transformer having primary and secondary coils the primary coil of which is in said output circuit, and means for com pensating for energy retransfer from the plate to the grid circuits, said means com prisin a condenser connected to the high potential side of the grid circuit and a coil connectingsaid primary coil with said condenser and coupled to said primary coil with a coupling substantially less than unity, the said coil and the said primary coil being each separately and closely coupled to the trans former secondary coil.

2. In combination, an electron discharge tube with its grid and plate electroded, a grid or input circuit, a plate or output cir cuit, a transformer having primary and secondary coils theprimary coil of which is in said output circuit, and means for compensating for energy retransfer from the plate to the grid circuits, said means comprising a condenser connected to the high potential side of the grid circuit and a coil connecting said primary coil with said condenser and coupled to said primary with a coupling substantially less than unity, the said coil and the said primary oil being closely and equally coupled to the transformer secondary coil.

3. In combination, an electron discharge tube with. its grid and plate electrodes, a grid or input circuit, a plate or output circuit, a transformer having primary and secondary coils the primary coil of which is in said output circuit, and means for compensating for energy retransfer from the plate to the grid circuits including an adjustable condenser connected to the high potential side of the grid circuit and a coil connecting said primary coil with said condenser, the said coil and the said primary coil being separately and equally coupled to the transformer secondary coil, the said adjustable condenser including means connected to the grid circuit operative to prevent detuning of the said grid circuit during adjustment of the condenser.

4. In combination, an electron discharge tube with its grid and late electrodes, a grid or input circuit, a p ate or output circult, a transformer having primary and secondary coils the primary coil of which is in will . trodes said output circuit, and means for compensating for energy retransfer from the plate to the grid circuits including a condenser connected to the high potential side of the grid circuit and a coil connecting said primary coil with said condenser to said primary coil with a coupling substantially less than unity, the said'coil and the said primary coil being separately and equally'coupled to the transformer secondary coil, the said coil and the condenser having values such that the product of the created potential and the capacity of the condenser is substantially equal to the electrostatic charge carried to the grid from the plate across the grid-plate capacity.

5. An electric circuit arrangement for neutralizing capacity coupling between the grid and plate circuits of an audion due to the capacity between the grid and plate electrodes comprising an audion having grid, plate and filament circuits, a transformer having primary and secondary coils, the primary coil being connected between the plate and the filament system of the audion, an auxiliary coil and a neutralizing capacity connected in series between the grid and the filament system, the said auxiliary coil being coupled to said primary coil pling substantially less than unity and the said auxiliary coil and the said primary coil being separately and equally coupled electromagnetically to the secondary coil of the transformer, the said primary and auxiliary coils having a ratio of turns equal to the ratio of the coupling capacity to the neutralizing capacity.

6. An electric circuit arrangement for neutralizing capacity coupling between the grid and plate circuits of an audi'on dueto the capacity between the grid and plate eleccomprising an audion having grid, plate and filament circuits, a transformer aving primary and secondary coils, the rimary coil being connected between the p ate and the filament system of auxiliary coil and a neutralizing capacity connected in series between the grid and the filament system, the said auxiliary coil being coupled to said primary coil with a coupling substantially less than unity and the said auxiliary coil and the said primary coil being separately and closely coupled electromagnetically to the secondary coil of the transformer, the said primary and auxiliary coils having a ratio of turns equal to the ratio of the coupling capacity to the neutralizing capacity.

7. A multi-stage amplifier comprising a plurality of transformer coupled audions, the said, transformer having a primary in the output circuit of one audion and a secondary in the input circuit of the second audion, and means for neutralizing for the capacity coupling between the grid and and coupled the said transformer having a with a couthe audion, an 7 plate circuits of said first audion, said means including a reverse potential coil and a capacity connected in series between the grid and the filament system of the said first audion, the said reverse potential coil and the primary of said transformer being coupled together with a coupling substantially less than unity and being separately and equally coupled to the secondary of the transformer. 8. A multi-stage amplifier comprising a plurality of transformer coupled audions, primary in the output circuit of one audion ondary in the input circuit of the second audion, and means for neutralizing for the capacity coupling between the gri and plate circuits of said first audion, said means including a reverse potential coil and a capacity connected in series between the rid and the filament system of the said 'rst audion, the said reverse potential coil and the primary of said transformer being coupled together with a coupling substantially less than unity and being separately, equally and closely coupled'to the secondary of the transformer.

9. A neutralized stage of amplification, comprising an electron discharge tube having grid and plate circuits, a third circuit coupled to one of said grid and plate cir' cuits, mechanism for neutralizing the ca pacity coupling between the other of said circuits.an'd the third circuit via the capacity between the grid and plate electrodes, said neutralizing mechanism comprising a coil connected between one of the electrodes and the filament system and an auxiliary coil and a neutralizing capacity connected in series between the other of these electrodes and the filament system, said auxiliary coil being coupled electromagnetically with ,a coupling substantially less than unity to the first coil, and both said coil and auxiliary coil being coupled separately and closely to said third circuit.

10. A neutralized stage of amplification, comprising an electron discharge tube having grid and plate circuits, a third circuit coupled to one of said grid and plate circuits, mechanism for neutralizing the capacity coupling between the other of said circuits and the third circuit via the ca pacity between the grid and plate electrodes, said neutralizing mechanism comprising a coil connected between one of the electrodes and the filament system and an auxiliary coil and a neutralizing capacity connected in series between the other of these electrodes and the filament system, said auxiliary coil being coupled electromagnctically with a coupling substantially less than unity to the first coil, and both said coil and auxand a seciliary coil being coupled closely and equally V comprising a plurality of stages, each stage having an electron discharge device containinga grid and a plate circuit and'mechanism in each stage for neutralizing the capacity coupling between the grid and plate circuits of such stage due to the capacity between the grid and plate electrodes, said neutralizing mechanism for each stage comprising a coil connected between one of the electrodes and the filament system and an auxiliary coil and a neutralizing capacity connected in series between the other otthese electrodes and the filament system, said auxiliary coil being coupled electromagnetically with a coupling substantially 15 less than unity to the first coil, and both said first coil and auxiliary coil of each stage being coupled separately and closely to acoil of the next adjacent stage.

Signed at New York city in the county 20 i of New York andState of New York this 10th day of September, A. D. 1926.

LESTER L. JONES. 

